Examples¶

Keyword Parser¶

The KeywordParser is designed to seek out and return chunks of text with specified start and end characters. This class takes three arguments that specify strings that begin and end each chunk of text, and the end of the file.

>>> kwargInput = ("// This a comment line\nset goodrun True\nmultiline line0\n"
>>>               "line1\nline2\n//Comment inside\n"
>>>               "multiline\nother1\nother2\nset done True\n")
>>> with open('kwargs.txt', 'w') as kwargFile:
>>>    kwargFile.write(kwargInput)
>>> with parsers.KeywordParser('kwargs.txt', keys=['set', 'multiline'],
>>>                            separators=['\n', '//']) as parser:
>>>    chunks = parser.parse()
>>> for num, chunk in enumerate(chunks):
>>>     print(num, ''.join(chunk)
0, 'set goodrun True'
1, 'multiline line0'
'line 1'
'line 2'
2, 'multiline'
'other1'
'other2'
3, 'set done True'

Pattern Reader¶

The PatternReader is designed to repeatedly return lines that match specified strings or regular expressions. The functionality is similar to grep, but with powerful features like yieldMatches(), shown below.

>>> lines = ("22:20:02:INFO    :root : Initializing ---------\n"
>>>          "22:20:10:DEBUG   :prepr: Prepping files to be uploaded\n"
>>>          "22:20:14:WARN    :prepr: FOUND 4 FILES, NOT 6 SPECIFIED, PROCEEDING\n"
>>>          "22:20:20:DEBUG   :compr: compressing 4 files\n"
>>>          "22:21:31:DEBUG   :compr: compression complete - 60 % compression ratio\n"
>>>          "22:22:05:DEBUG   :cnctr: Opening connection\n"
>>>          "22:22:09:INFO    :root : Beginning upload -------\n"
>>>          "22:22:11:DEBUG   :upldr: Launching upload of 1.21 Gb to destination\n"
>>>          "22:24:35:DEBUG   :closr: Experienced keyboard interupt\n"
>>>          "22:24:40:CRITICAL:upldr: LOST CONNECTION. ATTEMPTING CLEAN FAIL\n""
>>>          "22:24:42:DEBUG   :upldr: Launching clean fail routines\n"
>>>          "22:25:06:DEBUG   :upldr: Clean fail routines sucessful\n"
>>>          "22:25:56:INFO    :inspt: Likely source of error - keyboard interupt\n"
>>>          "22:26:23:INFO    :closr: Exiting processes ---------\n"
>>>          "22:26:41:INFO    :root : Process complete\n"
>>>          "22:26:42:DEBUG   :root : Error code: 1")
>>> filePath = 'patterntesting.txt'
>>>regexp = r'(\d{2}:\d{2}:\d{2}):(WARN|CRITICAL)\s*:([a-z]{5}):\s*(.*)'
>>>with open(filePath, 'w') as output:
>>>    output.write(lines)
>>>with PatternReader(filePath) as parser:
>>>    parser.searchFor('compr')
True
>>>    parser.line
'22:20:20:DEBUG   :compr: compressing 4 files'
>>>    parser.searchFor(regexp)
True
>>>    parser.line
'22:24:40:CRITICAL:upldr: LOST CONNECTION. ATTEMPTING CLEAN FAIL'

The PatternReader can also be used to produce matches on-the-fly and with little memory overhead as a generator

>> with parser:
>>     for match in parser.yieldMatches(regexp):
>>         print(match.groups()[0])
('22:20:14', 'WARN', 'prepr', 'FOUND 4 FILES, NOT 6 SPECIFIED, PROCEEDING')
('22:24:40', 'CRITICAL', 'upldr', 'LOST CONNECTION. ATTEMPTING CLEAN FAIL')

A great resource for building and testing python regular expressions is pythex.org.

See Also¶